Cardiovascular and respiratory responses to microinjection of L-glutamate into the caudal pressor area in conscious and anesthetized rats

The role of the caudal pressor area (CPA) in the maintenance of vasomotor tonus in anesthetized and decerebrate animals has been clearly established. In conscious animals, however, the participation of CPA in the cardiovascular control remains to be fully elucidated. In the present study, unilateral L-glutamate (L-Glu) (10 and/or 20 nmol/70 nl) microinjection into CPA, in conscious male Wistar rats (250-280 g) caused a significant increase in mean arterial blood pressure (MAP; control: 112 ± 1.9 mmHg; after 20 nmol L-Glu: 139 ± 4.5 mmHg, N = 12, P<0.05) and respiratory rate (control: 81 ± 3.5 breaths/min; after 10 nmol L-Glu: 92 ± 3 breaths/min, P<0.05; after 20 nmol L-Glu: 104 ± 5 breaths/min, N = 6, P<0.05). The subsequent anesthesia with urethane caused a significant increase in basal respiratory frequency (conscious: 81 ± 3.5 breaths/min; under urethane: 107 ± 1.3 breaths/min, N = 6, P<0.05). Anesthesia also significantly attenuated L-Glu-evoked pressor (conscious: deltaMAP = +27 mmHg; anesthetized: deltaMAP = +18 mmHg, P<0.05) and respiratory responses. These results suggest that glutamatergic receptors in the CPA are involved in cardiovascular and respiratory modulation in conscious rats.Universidade Federal do Espírito Santo Centro Biomédico Departamento de Ciências FisiológicasFAESA Faculdade de Saúde de VitóriaUniversidade Federal de São Paulo (UNIFESP) Disciplina de Fisiologia CardiovascularUNIFESP, Disciplina de Fisiologia CardiovascularSciEL

Alongamento muscular na dor lombar crônica inespecífica: uma estratégia do método GDS

The purpose of this study was to assess the effectiveness of stretching exercises of the Muscle and Joint Chains Godelieve Denys-Struyf (GDS) method in pain reduction, functional disability, increase global flexibility, and ability of the transversus abdominis muscle (TrA) contraction in individuals with nonspecific chronic low back pain. Fifty-five patients, from 18 to 60 years-old, participated in this study divided into two groups: the Stretching Group (n=30) underwent stretching exercises twice a week; the Control Group (n=25) was subjected only to evaluation. Pain was assessed by a visual analogue scale, functional disability by the Oswestry Questionnaire, global flexibility by third finger to the ground test and the ability of TrA contraction by a pressure biofeedback unit. Three evaluations were performed, starting after 8 and 16 weeks from the beginning. Significance level was &#945;O objetivo deste estudo foi verificar a eficácia do alongamento muscular, usando uma sequência proposta pelo Método Godelieve Denys-Struyf (GDS) na redução da dor, na incapacidade funcional, no aumento da flexibilidade global e na capacidade de contração do músculo transverso do abdome (TrA), em indivíduos com dor lombar crônica inespecífica. Participaram 55 pacientes, de 18 a 60 anos, divididos em dois grupos: Grupo Alongamento (n=30) submetido a exercícios de alongamento, duas vezes por semana, e Grupo Controle (n=25) que não realizou tratamento. A dor foi avaliada pela escala visual analógica; a incapacidade funcional, pelo Índice de Oswestry; a flexibilidade global, pelo terceiro dedo ao solo; e a capacidade de contração do TrA, pela unidade de biofeedback pressórico. Foram realizadas três avaliações, inicial, após 8 e 16 semanas da inicial. Foi considerado nível de significância de &#945

Participation of 5-HT and AT 1 Receptors within the Rostral Ventrolateral Medulla in the Maintenance of Hypertension in the Goldblatt 1 Kidney-1 Clip Model

The hypothesis that changes in neurotransmission within the rostral ventrolateral medulla (RVLM) are important to maintain the high blood pressure (BP) was tested in Goldblatt one kidney-one clip hypertension model (1K-1C). Male Wistar rats were anesthetized (urethane 1.2 g/kg, i.v.), and the effects of bilateral microinjections into the RVLM of the following drugs were measured in 1K-1C or control groups: glutamate (0.1 mol/L, 100 nL) and its antagonist kynurenic acid (0.02 mol/L, 100 nL), the angiotensin AT 1 receptor antagonist candesartan (0.01 mol/L, 100 nL), and the nonselective 5-HT receptor antagonist methiothepin (0.06 mol/L, 100 nL). Experiments in 1K-1C rats were performed 6 weeks after surgery. In anesthetized rats glutamate response was larger in hypertensive than in normotensive rats (H: Δ67 ± 6.5; N: Δ43 ± 3.54 mmHg). In contrast, kynurenic acid microinjection into the RVLM did not cause any change in BP in either group. The blockade of either AT 1 or 5-HT receptors within the RVLM decreased BP only in 1K-1C rats. A largest depressor response was caused by 5-HT receptor blockade. The data suggest that 5-HT and AT 1 receptors act tonically to drive RVLM in 1K-1C rats, and these actions within RVLM contribute to the pathogenesis of this model of hypertension

Role of Renal Nerves in the Treatment of Renovascular Hypertensive Rats with L

The purpose was to determine the role of renal nerves in mediating the effects of antihypertensive treatment with L-arginine in a renovascular hypertension model. The 2K1C (two-kidney one-clip model) hypertensive rats were submitted to bilateral surgical-pharmacological renal denervation. The animals were subdivided into six experimental groups: normotensive control rats (SHAM), 2K1C rats, 2K1C rats treated with L-arginine (2K1C + L-arg), denervated normotensive (DN) rats, denervated 2K1C (2K1C + DN) rats, and denervated 2K1C + L-arg (2K1C + DN + L-arg) rats. Arterial blood pressure, water intake, urine volume, and sodium excretion were measured. The 2K1C rats exhibited an increase in the mean arterial pressure (MAP) (from 106 ± 3 to 183 ± 5.8 mmHg, P<0.01), whereas L-arg treatment induced a reduction in the MAP (143 ± 3.4 mmHg) without lowering it to the control level. Renal nerve denervation reduced the MAP to normotensive levels in 2K1C rats with or without chronic L-arg treatment. L-arg and denervation induced increases in water intake and urine volume, and L-arg caused a significant natriuretic effect. Our results suggest that renal sympathetic activity participates in the genesis and the maintenance of the hypertension and also demonstrate that treatment with L-arg alone is incapable of normalizing the MAP and that the effect of such treatment is not additive with the effect of kidney denervation